pjsip on has been running on iPhone and iPod Touch for quite a while. Samuel Vinson (also responsible for making possible VoIP on Nintendo DS) was the first to announce a successful port to iPhone and iPod Touch even before the official SDK became available.

Siphon has already been available for developers and also on Cydia, an alternative distribution platform for iPhone applications. voiphone is another project starting up, based on sound device code from Siphon.

Now another milestone is reached, because an iPhone softphone called SipPhone on iPhone (how many phones can you have in a sentence!), has been released on the official App Store by VNet Corp of Shanghai. This means users unable or unwilling to install Cydia are also able to enjoy VoIP over Wi-fi with their favourite providers, instead of dictated by which client you use.

(For those reading on a computer with iTunes or on the iPhone itself here is the direct link to SipPhone on App Store.)

So how does it work? After downloading from App Store, following the installation instructions, I was able to add Teluu’s sipgate.co.uk account (look, No SIM!):

Main SIP account settings

Additional SIP account settings (optional)

I was then able to choose from my Contacts and make a call as normal. I didn’t do any extensive voice quality testing, just some quick calls. I will try to record some conversations to illustrate better the voice quality.

Another feature that needs pointing out is the ability to have multiple accounts. It was quite easy to toggle which account is active at any one time. The pjsip.org SIP domain uses OpenSER OpenSIPS, so I know this client is compatible with it.

Multiple accounts support for the iPhone SIP client

The source of the application is available at their forum, it seems you can get it even if you are not a customer. This is beyond the requirements of the GPL, so nice touch on VNET Corp people.

I still haven’t been unable to compile it, so as can be seen I have a question pending there.

Overall of course the main issue of VoIP over wi-fi in iPhone remains: no background task. That means, unlike other mobile devices such as Nokia which uses Symbian, it cannot receive any calls while you are doing something else.